This invention relates to pro-drugs of certain 3-hydroxybenzothiophenes which have a 2-enamido side chain. More particularly it relates to cyclic pro-drugs of N-alkenyl-3-hydroxybenzo[b]thiophene-3-carboxamides which exhibit cyclooxygenase and 5-lipoxygenase inhibitory action, pharmaceutical compositions thereof, and the use thereof to treat various mammalian diseases.
U.S. Pat. No. 4,760,086, issued Jul. 26, 1988, describes a large number of N-alkenyl-3-hydroxybenzo[b]-thiophene-3-carboxamides of formula (I) ##STR1## wherein each of X.sub.1 -X.sub.4, R and R.sup.1 -R.sup.4 are broadly defined as lower alkyl, aryl, heteroaryl, lower cycloalkyl, benzyl, lower alkenyl or lower alkynyl any of which may be substituted by a variety of substituents.
Said compounds are disclosed to be effective inhibitors of cyclooxygenase and 5-lipoxygenase and, therefore, of value in the treatment of inflammation, pain, fever and other prostaglandin and/or leukatriene mediated diseases.
U.S. Pat. No. 4,656,265, issued Apr. 7, 1987, describes cyclic pro-drugs of non-steroidal anti-inflammatory oxicams. In said pro-drugs, the parent oxicams are chemically modified to form a fused 1,3-oxazine ring system, which, in vivo, is cleaved to restore the parent compound.